scholarly journals Verification of visibility forecasts from NWP model with satellite and surface observations

MAUSAM ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 603-616
Author(s):  
ADITI ADITI ◽  
JOHNP. GEORGE ◽  
M.DAS GUPTA ◽  
E.N. RAJAGOPAL ◽  
SWATI BASU
2020 ◽  
Vol 27 (6) ◽  
Author(s):  
Erik Gregow ◽  
Anders V. Lindfors ◽  
Siebe H. van der Veen ◽  
David Schoenach ◽  
Siebren de Haan ◽  
...  

2011 ◽  
Vol 139 (6) ◽  
pp. 1960-1971 ◽  
Author(s):  
Jakob W. Messner ◽  
Georg J. Mayr

Abstract Three methods to make probabilistic weather forecasts by using analogs are presented and tested. The basic idea of these methods is that finding similar NWP model forecasts to the current one in an archive of past forecasts and taking the corresponding analyses as prediction should remove all systematic errors of the model. Furthermore, this statistical postprocessing can convert NWP forecasts to forecasts for point locations and easily turn deterministic forecasts into probabilistic ones. These methods are tested in the idealized Lorenz96 system and compared to a benchmark bracket formed by ensemble relative frequencies from direct model output and logistic regression. The analog methods excel at longer lead times.


2015 ◽  
Vol 26 (1) ◽  
pp. 163-181 ◽  
Author(s):  
Ian G. Robertson

AbstractIn the 1960s, the Teotihuacan Mapping Project (TMP) focused an ambitious, multiyear survey program on the pre-Columbian urban center of Teotihuacan. In addition to creating a highly detailed map, the TMP made systematic records of surface remains and collected nearly one million artifacts from roughly 5,000 provenience tracts. Taken together, the spatial, descriptive, and artifactual data collected by the TMP still constitutes one of the most extensive and most detailed records in existence for any ancient city. This paper characterizes and provides an update on TMP surface observations, particularly as they exist in digital format. Several analytical case studies illustrate substantive ways in which these data have been used in the decades since the TMP survey to investigate the culture and history of ancient Teotihuacan. The utility of extensive surface survey data for investigating key urban organizational elements such as neighborhoods and social districts is briefly considered, along with the growing importance of the TMP collections and records as increasingly large parts of Teotihuacan are lost to urban sprawl and destructive agricultural practices.


2012 ◽  
Vol 140 (3) ◽  
pp. 1014-1022 ◽  
Author(s):  
Tuomo Lauri ◽  
Jarmo Koistinen ◽  
Dmitri Moisseev

When making radar-based precipitation products, a radar measurement is commonly taken to represent the geographical location vertically below the contributing volume of the measurement sample. However, when wind is present during the fall of the hydrometeors, precipitation will be displaced horizontally from the geographical location of the radar measurement. Horizontal advection will introduce discrepancies between the radar-measured and ground level precipitation fields. The significance of the adjustment depends on a variety of factors related to the characteristics of the observed precipitation as well as those of the desired end product. In this paper the authors present an advection adjustment scheme for radar precipitation observations using estimated hydrometeor trajectories obtained from the High-Resolution Limited-Area Model (HIRLAM) MB71 NWP model data. They use the method to correct the operational Finnish radar composite and evaluate the significance of precipitation advection in typical Finnish conditions. The results show that advection distances on the order of tens of kilometers are consistently observed near the edge of the composite at ranges of 100–250 km from the nearest radar, even when using a low elevation angle of 0.3°. The Finnish wind climatology suggests that approximately 15% of single radar measurement areas are lost on average when estimating ground level rainfall if no advection adjustment is applied. For the Finnish composite, area reductions of approximately 10% have been observed, while the measuring area is extended downstream by a similar amount. Advection becomes increasingly important at all ranges in snowfall with maximum distances exceeding 100 km.


2009 ◽  
Vol 137 (1) ◽  
pp. 495-503 ◽  
Author(s):  
Timothy A. Coleman ◽  
Kevin R. Knupp ◽  
Daryl Herzmann

Abstract A visually impressive undular bore moved across much of Iowa on 2 October 2007, and video animations were captured by numerous Webcams. The bore was sampled very well by Doppler radar at close range, and also by the high-density mesoscale network of surface stations in place over Iowa and 1-min Automated Surface Observing System (ASOS) surface data at Des Moines, Iowa. Radar and surface observations are presented, along with a brief analysis of the structure of the bore.


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